Clean mushrooms. Remove stems, chop stems finely. Sauté minced mushroom stems, onion and bell pepper in 2 Tbsp. butter for 5 minutes (do not brown). Add crab meat. Remove from heat. Stir in seasonings and bread crumbs – taste and adjust seasonings. Oil baking sheet.
Toss mushroom caps with a generous drizzle of oil.
Fill caps with stuffing.
Drizzle stuffed mushrooms with 2 Tbsp. melted butter, sprinkle generously with Parmesan cheese. Bake at 350 degrees for 15 to 20 minutes. Raise oven to 550 degrees briefly to brown lightly. Remove from oven and serve immediately.